function sum(x, y) {
    return x + y;
}

function sub(x, y) {
    return x - y;
}

function mul(x, y) {
    return x * y;
}

function div(x, y) {
    return x / y;
}
module.exports = {
    sum: sum,
    sub: sub,
    mul: mul,
    div: div
}